Energy-saving Application of KERUN Inverter in Agitator Units
I. Abstract:
This paper primarily discusses the wide application of inverters in agitators and verifies, through actual data, the effectiveness, reliability, and significant energy-saving effects of variable frequency speed regulation on agitation-type loads.
II. Keywords:
Agitation, Variable Frequency Speed Regulation, Energy Saving
III. Analysis of Inverter Application
Agitator (dewatering) units feature high motor power, large starting current, and long starting times. Furthermore, regardless of changes in material composition or quantity, once started and switched from star-delta connection, they operate directly at line frequency. This leads to high noise, severe mechanical wear, and significant energy waste. Additionally, the control circuitry cannot be simplified, causing inconvenience for operators. Adopting inverter energy-saving technology for retrofitting can substantially reduce the starting current, simplify the control circuits, and allow real-time adjustment of motor speed during system operation based on actual conditions. Based on our company's retrofitting experience, typical energy savings range from 15% to 35%, representing considerable economic benefits.
For example, a standard agitator unit often consists of three machines, each with a motor power of 400KW. Two application schemes are available for selection:
Scheme 1: Employ one inverter-based energy-saving control system to drive all three units. The control system is used only for variable frequency starting. After startup is complete, the system switches to line frequency operation. Only one of the three units can operate under variable frequency control at any time.
Figure 1.1 Wiring Diagram 1 of Inverter on Agitator
Scheme 2: Adopt a "one-inverter-per-unit" approach for energy-saving retrofitting. Each unit forms an independent system while also being interconnected. Speeds can be adjusted individually.
Figure 1.2 Wiring Diagram 2 of Inverter on Agitator
Between the two schemes, the first requires lower investment but involves more complex control circuits, is time-consuming for maintenance and troubleshooting, and demands higher technical expertise. The second scheme offers the most pronounced energy-saving and consumption-reducing effects and allows for establishing independent operating procedures tailored to different products.
IV. Energy-saving Effect
Taking the "one-inverter-per-unit" scheme as an example: Assuming operation for 10 hours per day, 25 days per month, with an electricity cost of 0.75 RMB/kWh, and an energy-saving efficiency calculated at 20% compared to the original operating condition, the energy savings per unit are as follows:
Monthly electricity cost savings: 400KW * 10 hours * 25 days * 20% * 0.75 RMB/kWh = 15,000 RMB
Typically, the investment cost for all inverter equipment can be recovered within one year. Additionally, it reduces waste of materials, water, etc.
V. Conclusion
With the rapid development of power electronics technology and the increasing sophistication of inverter technology, more and more variable frequency speed regulation systems are being applied across various industries. Their excellent control performance and remarkable energy-saving effects bring substantial economic benefits to enterprises.